Multipath error mitigation using self‐encoded spread spectrum for navigation

Abstract

Self-encoded spread spectrum (SESS) is a novel modulation technique that acquires its spreading sequence from the random input data stream rather than using the traditional pseudo-random-code generators. It has been shown that the memory in SESS can improve the system performance significantly in fading channel. In this study the authors analyse the tracking error of SESS system in the presence of multipath Rayleigh fading channels. Code Shuffling is introduced to randomise the spreading code, which in turn mitigates the effect of reflected path component and enhances the accuracy and performance of iterative detection (ID) against multipath effects. The performance comparison of SESS with C/A code is investigated with the main focus on short multipath delay scenarios. The results demonstrate that ID can significantly mitigate the pseudorange multipath error without any bandwidth expansion.

Multipath error mitigation using self‐encoded spread spectrum for binary‐offset‐carrier signals

“…= b k , we can see that the first term successfully decode the direct path component. Code shuffling reduces the magnitude of the second term and thereby significantly enhances the performance of the ID [1].…”

“…Self-encoded spread spectrum (SESS) has been successfully implemented with global positioning system (GPS) in [1]. SESS with iterative detection (ID) was shown to outperform conventional coarse/acquisition (C/A) code especially in multipath channel.…”

“…Consequently, SESS provides rare advantages over the traditional pseudo-random (PR) coded systems because of retransmission of the data bit in subsequent spreading sequences [3,4]. Since SESS assumes a purely random data, the alternating pattern of BOC may affect the navigation performance, which was not an issue in SESS with GPS [1]. However, we hope that the powerful multipath immunity of SESS overcome confronted challenges of SESS with BOC.…”

“…It is our prospect that BOC combined with SESS ID can provide significantly improved navigation scheme in practical channel scenarios with fading and multipath. We employ the same criteria used in [1] for fair comparison to examine the proposed navigation system such as early-minus-late (EML) [13,16] and early/late slope (ELS) [14] techniques. SESS scheme and BOC signals are reviewed in Section 2.…”

Low-complexity code tracking loop with multipath diversity for GNSS over multipath fading channels

“…For closely spaced multipath scenarios, a class of the improved DLLs share the same underlying structure of narrowing the early-late spacing and main lobe of the cross-correlation function [6]- [9]. While in [10], the authors propose a new discriminator function which is insensitive to short multipath signals with delay less than one half the correlator spacing.…”